Osso Buco...in the Crockpot

Tonight my parents came home and since I had lots of errands to run and things to do around the house before their arrival I wanted a dinner I could throw into the crockpot -- something warm and wholesome. Thus was born my version of a crockpot Osso Buco:

Ingredients:
*1 Large onion sliced into thin wedges
*3 Large carrots, sliced
*4 Stalks celery, sliced
*4 Cloves of garlic, sliced
*4 Beef shanks (3-4 lbs)
*1 1/2 TBSP Herbs d'Provence
*2 Tsp Salt
*2 Tsp Black Pepper
*1 C Beef Broth
*1 TBSP Beef Bullion
*1 8 oz can Tomato puree
*1 C Dry White Wine
*1/8 C flour
Garnish:
*1 small clove garlic, minced
*Zest of 1 large lemon
*Juice of 1/2 large lemon
*1/2 C chopped parsley

1. Coat crockpot with cooking spray. Place salt, pepper, beef bullion, tomato puree in crockpot with wine and beef broth, mix well. Season beef shanks with salt and pepper - brown on the stove. After both sides have browned, add meat and veggies to crockpot. Cover, cook on LOW 7-8 hours or on HIGH 4-5 hours, or until tender.
2. Transfer shanks and veggies to serving platter; cover with foil to keep warm. Turn crockpot to HIGH, mix flower with a few TBSP of water and mix until smooth. Stir liquid into cooking liquid to create sauce. Cover; cook on HIGH 15 minutes or until thickened.
3. Serve sauce over shanks and vegetables. Combine parsley, minced garlic, lemon zest and lemon juice. Sprinkle parsley combination over shanks.

This is excellent with a crusty bread.